#include <iostream>
using namespace std;

int main(int argc, char const *argv[])
{
  int a = 10;
  // 创建引用
  int &b = a;
  cout << "a = " << a << endl;
  cout << "b = " << b << endl;
  b = 20;
  cout << "a = " << a << endl;
  cout << "b = " << b << endl;
  return 0;
}